1. Field of the Invention
The present invention relates to an image pickup apparatus such as an electronic camera for recording a digital still image.
2. Related Background Art
In recent years, with the advent of high-performance personal computers and high-resolution monitors, a demand has arisen for an apparatus that can input and store images such as a document, a color drawing, a photograph, and the like as digital still images with a high resolution For this purpose, an image pickup apparatus such as an electronic still camera or the like is used.
However, the image quality of the electronic camera depends on the number of pixels of an image pickup element such as a CCD image sensor built therein In general, a high-quality image can be picked up at the telephoto side but cannot be picked up at the wide-angle side In order to obtain a high-quality image, a means for increasing the number of pixels of the image pickup element and a means for divisionally picking up a single image in the vertical and horizontal directions by changing the image pickup range upon rotation of a mirror, and synthesizing a plurality of picked-up images using image correlation to obtain a single image (image division method; Japanese Laid-Open Patent Application No. 6-141228) have been proposed
However, according to the former means, since the cost of the image pickup element rises, the apparatus becomes expensive as a whole. Also, according to the latter means, when the size or density of an object changes, the number of divisions in the image pickup operations cannot be changed accordingly. For this reason, the image quality varies considerably depending on the size or density of the object.